定义一个大学生类Graduate，私有数据成员：姓名，学号，校名，并为它定义带参数的构造函数、拷贝构造函数、析构函数和输出数据成员值的print( )公有成员函数，另定义研究生类Postgraduate，它以公有继承方式派生于类Graduate，新增加“研究方向、导师名”两个私有数据成员，并定义带参数的构造函数，拷贝构造函数、析构函数和输出研究生数据的print( )公有成员函数，另外，要求学号自动增加，且Graduate和Postgraduate的学号起始值不同。在主函数中定义派生类对象进行测试。-Definition of a college class Graduate, private data members: name, student number, school name, and define parameters for its constructor, copy constructor, destructor and member of the value of the output data print () public member function, the other definitions Graduate Class of Postgraduate, it to public inheritance derived class Graduate, additional " research, teachers were"　two private data members, and define the parameters of the constructor, copy constructor, destructor and output data of the print graduate () public member function In addition, student number required automatic increases, and the Graduate and Postgraduate initial value of learning different number. Defined in the main function to test the derived class object.